Scientific Series

Polluted air is found in most cities. It is caused by burning coal, oil, and natural gas. Polluted air is not only unpleasant, it is harmful. Polluted air can cause respiratory infections, lung cancer, allergies, and other diseases. Polluted air also harms plants and reduces crop yields.Motor vehicles are a major source of air pollution in the United States, Carbon monoxide, hydrocarbons, and nitrogen oxides are the main pollutants in auto exhaust. They are the result of burning gasoline in a car's engine.Carbon monoxide is a colourless, odorless gas. It is poisonous. Carbon monoxide gas in auto exhaust can cause suffocation. Hydrocarbons and nitrogen oxides are gases which cause photochemical smog. Photochemical smog gases in the presence of sunlight. One of the products of the change is ozone gas. Ozone irritates the linings of the nose and throat. It makes one's eyes water and sting. Many cities have photochemical smog. Sometimes no wind blows and the air is still for a long time. When this occurs, photochemical smog can build up quickly dangerous amounts. The smog can cause sickness and death.The design of the gasoline engine has been changed somewhat to reduce air pollution from exhaust. Some governments require that automobile engines meet certain pollution standards. To meet these standards, antipollution devices are added to the engines. These help to reduce the harmful gases released in auto exhaust.Some gasoline contains lead. When lead is present in gasoline, it becomes a pollutant in exhaust. Lead pollutants in the air can be harmful to people, other animals, and plants. Lead poisoning can cause permanent damage to the brain and nervous system. New cars are designed to use low-lead or lead-free gasoline.Many scientists believe that the gasoline engine should be replaced. Turbine engines use gasoline fuel more efficiently. Engines which use natural gas or hydrogen for fuel produce few pollutants. Automobiles operated by rechargeable electric batteries produce few pollutants.Sulfur dioxide and particulates are major air pollutants. They are produced by the burning of fuels in homes and industries. Sulfur dioxide is a colourless gas with a bad odor. Sulfur dioxide can cause respiratory problems and it is poisonous. Some of the sulfur dioxide in polluted air combines with water vapour to form an acid. The acid harms plants, corrodes metal, and damages stone. Particulates are particles of all sizes that emitted into the air. Ash, dust, and smoke are particulates. They contribute to smog. Particulates vary in their chemical structure. Some cause respiratory ailments.Pollution by sulfur dioxide and particulates can be controlled. Sulfur dioxide pollutants can be reduced by burning kinds of oil and coal which do not contain much sulfur. Also, the sulfur can be removed before the fuels are burned. Particulates can be removed by filters placed in smokestacks. Most large cities have laws which regulate the release of air pollutants by industries. However, the laws are not always enforced.

QUESTION

1) What is air pollution? (2 marks)2) How does air get polluted referring to the text? (4 marks)3) Is it true that air pollution has no consequences? (justify your answer referring to the text) (6 marks)4) Is there or are there any solution(s) to prevent air pollution thoroughly? (Referring to the text, illustrate your arguments) (8 marks)